Sodium-solvent fire

Interactions with the carbon surface can make the recovery of certain solvents, such as ketones and chlorinated hydrocarbons, difficult. Ketones and aldehydes can polymerize, releasing large amounts of heat. When this happens in a part of the bed with poor heat transfer, the temperature can reach the ignition point of the solvent. Fires always start with hot-spots in parts of the bed where the airflow is reduced due to poor design. The susceptibility of the carbon bed to autoignition can be reduced by removing soluble alkali sodium and potassium salts, that may be present as impurities in the activated carbon and which can function as combustion and gasification catalysts [29]. 

Carbon tetrachloride must not be dried with sodium as an explosion may result. Fire extinguishers containing this solvent (e.g., Pyrene ) cannot therefore be applied to a fire originating from sodium. 

For burning oil (or organic solvents), do not use water as it will only spread the fire a mixture of sand and sodium bicarbonate is very effective. 

The drying of flammable solvents with sodium or potassium metal and metal hydrides poses serious potential fire hazards and adequate precautions should be stressed. 

Zinc in contact with wood Zinc is not generally affected by contact with seasoned wood, but oak and, more particularly, western red cedar can prove corrosive, and waters from these timbers should not drain onto zinc surfaces. Exudations from knots in unseasoned soft woods can also affect zinc while the timber is drying out. Care should be exercised when using zinc or galvanised steel in contact with preservative or fire-retardant-treated timber. Solvent-based preservatives are normally not corrosive to zinc but water-based preservatives, such as salt formulated copper-chrome-arsenic (CCA), can accelerate the rate of corrosion of zinc under moist conditions. Such preservatives are formulated from copper sulphate and sodium dichromate and when the copper chromium and arsenic are absorbed into the timber sodium sulphate remains free and under moist conditions provides an electrolyte for corrosion of the zinc. Flame retardants are frequently based on halogens which are hygroscopic and can be aggressive to zinc (see also Section 18.10). 

Add 1 ml. of the alcohol-firee ether to 0-1-0-16 g. of finely-powdered anhydrous zinc chloride and 0-5 g. of pure 3 6-dinitrobenzoyl chloride (Section 111,27,1) contained in a test-tube attach a small water condenser and reflux gently for 1 hour. Treat the reaction product with 10 ml. of 1 5N sodium carbonate solution, heat and stir the mixture for 1 minute upon a boiling water bath, allow to cool, and filter at the pump. Wash the precipitate with 5 ml. of 1 5N sodium carbonate solution and twice with 6 ml. of ether. Dry on a porous tile or upon a pad of filter paper. Transfer the crude ester to a test-tube and boil it with 10 ml. of chloroform or carbon tetrachloride filter the hot solution, if necessary. If the ester does not separate on cooling, evaporate to dryness on a water bath, and recrystallise the residue from 2-3 ml. of either of the above solvents. Determine the melting point of the resulting 3 5-dinitro-benzoate (Section 111,27). 

Acylation of diethyl succinate by ethyl trifluoroacetate in presence of sodium hydride and in absence of a solvent is hazardous, fire or explosion occurring on 2 occasions some 10-20 min after adding a tittle of the succinate to the hydride-trifluoroacetate premixture at 60°C. Presence of a solvent appears to eliminate the hazard. 

MRH Barium chlorate 5.06/83, calcium chlorate 5.61/77, potassium chlorate 6.07/76, sodium bromate 4.98/80, sodium chlorate 7.32/75, zinc chlorate 6.11/76 Dry finely divided mixtures of red (or white) phosphorus with chlorates, bromates or iodates of barium, calcium, magnesium, potassium, sodium or zinc will readily explode on initiation by friction, impact or heat. Fires have been caused by accidental contact in the pocket between the red phosphorus in the friction strip on safety-match boxes and potassium chlorate tablets. Addition of a little water to a mixture of white or red phosphorus and potassium iodate causes a violent or explosive reaction. Addition of a little of a solution of phosphorus in carbon disulfide to potassium chlorate causes an explosion when the solvent evaporates. The extreme danger of mixtures of red phosphorus (or sulfur) with chlorates was recognised in the UK some 50 years ago when unlicenced preparation of such mixtures was prohibited by Orders in Council. 

Requirements for safe storage of powdered Al, Hf, Mg, Ti, Zn and Zr are outlined. Fires are best extinguished with various fluxes, trimethyl boroxine, asbestos fines ( ), talc, graphite, sodium chloride, soda ash, lithium chloride or powdered dolomite [ ] Slurries of Al, Cd, Cu, Ge, In, Ni, Pb, Sn or Zn produced by metal atom-solvent cocondensation at — 196°C are extremely active chemically [2], and would be pyrophoric on exposure to air. 

Class B Fires. These are fires in flammable liquids (oils, gasoline, solvents, etc.), where a blanketing or smothering effect is essential to put the fire out. This effect keeps oxygen away from the fuel, and can be obtained with carbon dioxide, dry chemical (essentially sodium bicarbonate), foam, or a vaporizing-liquid type of extinguishing agent. Water is most effective when used as a fine spray or mist... 

Carbon tetrachloride commonly was employed as a cleaning solvent, although its considerable toxicity entails considerable hazard when used indiscriminately. It has been used as a fire-extinguishing fluid for petroleum fires, but its toxicity and tendency to form still more toxic carbonyl dichloride makes it undesirable for confined areas. The common laboratory practice of removing traces of water from solvents with metallic sodium should not be applied to halogenated compounds carbon tetrachloride-sodium mixtures are shock sensitive and can detonate. 

Sodium chlorite solution is a powerful oxidizer and can react explosively with acidic materials. It should be stored safely, ideally out of the direct heat of the sun and away from all other materials. Spills and bulk tanks should not be permitted to dry out. Any contact of crystalline sodium chlorite with organics such as oil, solvents, wood, or cotton gloves can result in a fire or an explosion. 

Sodium residues. Bottles containing sodium wire previously used for solvent drying constitute a fire and explosion hazard. The sodium, sometimes heavily coated with hydroxide or oxide film, should be covered with propan-2-ol and set aside with occasional swirling until all the sodium particles are destroyed (at least 2 hours). The contents of the bottle should then be poured into a large excess of water (water should not be added to the bottle) and the bottle washed out several times with industrial spirit. Only then can the bottle be safely rinsed with water. 

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